<!--
 * @Description: ID选择器
 * @Author: rendc
 * @Date: 2021-08-05 16:36:39
 * @LastEditors: rendc
 * @LastEditTime: 2021-08-05 16:40:50
-->
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>ID选择器</title>
  <style>
    #app {
      height: 200px;
    }

    .myDiv {
      color: orange;
    }

    #one {
      border: 1px solid greenyellow;
    }
  </style>
</head>

<body>
  <div id="app">
    <div class="myDiv" id="one">1</div>
    <div class="myDiv" id="two">2</div>
    <div class="myDiv" id="three">3</div>
  </div>
</body>

</html>